#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <assert.h>

#include "bitopz.h"

#ifdef __GNUC__

#else

int __ffs(int x)
{
   int i;
   assert(&x);

   for (i=0; i<BITS_PER_LONG; i++) {
      if (x & (1UL<<i))
      return i+1;
   }
   return 0;
}

int __fls(int x)
{
   int i;
   assert(&x);

   for (i=BITS_PER_LONG-1; i>=0; i--) {
      if (x & (1UL<<i))
      return i+1;
   }
   return 0;
}

#endif

unsigned long __bit_weight(unsigned long x)
{
   unsigned long n = 0;
   assert(&x);
   while (x) {
      x = x & (x - 1);
      n++;
   }
   return n;
}

unsigned long bitweight32(unsigned long w)
{
   register unsigned long res;
   assert(&w);
   res = w - ((w >> 1) & 0x55555555);
   res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
   res = (res + (res >> 4)) & 0x0F0F0F0F;
   res = res + (res >> 8);
   return (res + (res >> 16)) & 0x000000FF;
}

unsigned long bitweight16(unsigned long w)
{
   register unsigned long res;
   assert(&w);
   res = w - ((w >> 1) & 0x5555);
   res = (res & 0x3333) + ((res >> 2) & 0x3333);
   res = (res + (res >> 4)) & 0x0F0F;
   return (res + (res >> 8)) & 0x00FF;
}

unsigned long bitweight8(unsigned long w)
{
   register unsigned long res;
   assert(&w);
   res = w - ((w >> 1) & 0x55);
   res = (res & 0x33) + ((res >> 2) & 0x33);
   return (res + (res >> 4)) & 0x0F;
}


static const unsigned char byte_rev_table[256] = {
	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
	0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
	0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
	0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
	0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
	0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
	0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
	0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
	0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
	0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
	0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
	0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
	0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
	0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
	0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
};

unsigned char bitrev8(unsigned char x)
{
   assert(&x);
   return byte_rev_table[x];
}

unsigned short bitrev16(unsigned short x)
{
   assert(&x);
   return (byte_rev_table[x & 0xff] << 8) | byte_rev_table[x >> 8];
}

unsigned long bitrev32(unsigned long x)
{
   assert(&x);
   return (byte_rev_table[x & 0xff] << 24) | (byte_rev_table[(x >> 8) & 0xff]) << 16
               | (byte_rev_table[(x >> 16) & 0xff]) << 8 | (byte_rev_table[(x >> 24) & 0xff]);
}

void bitrev(unsigned char *buf, int size)
{
   unsigned char *i = buf, *j = buf + size - 1;
   assert(buf);
   assert(size >= 0);

   while (i < j) {
      unsigned char t = *i;
      *i = byte_rev_table[*j];
      *j = byte_rev_table[t];
      i++;
      j--;
   }
   if (i == j)
      *i = byte_rev_table[*j];
}

